| 摘要 |
PURPOSE:To improve the shelf life of direct reversal positive photographic paper by incorporating formaldehyde or compd. contg. the formaldehyde as the constituting material into the paper. CONSTITUTION:The paper contains the formaldehyde or the compd. contg. the formaldehyde as the constituting material. The compd. contg. the formaldehyde as the constituting material to be used is preferably the compd. which generates the partly liberated formaldehyde; for example, a melamine resin which is used as a wet strength agent for paper is preferable as said resin contributes to the improvement of the shelf life of the photographic paper and the strength of the paper. The amt. of the liberated formaldehyde is preferably <=0.2wt% by the weight of the paper. The shelf stability improves but the liberated formaldehyde cures the gelatin used as a binder for an emulsion layer by reacting therewith when the amt. of the liberated formaldehyde exceeds 0.2wt%. A photographic processing liquid is then made difficultly penetratable, by which the failure in a developing process and an undesirable decrease of the tone are caused. In addition, the part which is ought to be black is not made black. |
